Vray dirt use in houdini vs 3dsmax

[Silvoni]

Hi everyone am having trouble making vray dirt work as a mask, in 3ds max you can invert the colors and use it as a mask and connect a vraycolor to the occluded to make more intense the mask, but in houdini is not working the same way. if you use a black color you can not see anything but if you use another color works.

[david.anastacio]

Hi everyone am having trouble making vray dirt work as a mask, in 3ds max you can invert the colors and use it as a mask and connect a vraycolor to the occluded to make more intense the mask, but in houdini is not working the same way. if you use a black color you can not see anything but if you use another color works.

Hi Silvoni,

The black color doesn't work on the occluded slot because your un-occluded color is also black, so the dirt is blending between black and black. You should use white as your occluded color.

Best,
David.

[Silvoni]

Hi david.anastacio thanks for the response, in the vray dirt I have the occluded color in white, im trying to use vray dirt as a white and black mask, this works in vray for max.

[david.anastacio]

Hi again Silvoni,

You mentioned:

if you use a black color you can not see anything but if you use another color works.

And in the 3rd screenshot I can see that the dirt unoccluded color is also set to black, this does not output white and black, only black. Have you tried using the debug mode in the dirt node to see what its output is?

This works exactly the same in Houdini and 3dsmax, so there must be something strange in the setup, could you upload your setup?


Best,
David.

[Silvoni]

Thanks again, Here is the file

[david.anastacio]

Hi again Silvoni,

The issue is not the dirt, it's your color picker You need to be carefull with the colors you pick, they might have a zero alpha (this is a Houdini thing, not V-Ray). The color node is a vector4 with 4 floats, red + green + blue + ALPHA, and if your alpha is set to 0.0 that will make your color fully transparent.




You should use the debug mode to check how the shader/maps are looking at different points, during IPR use the cyan flag in the nodes to visualize that node.

Best,
David.

[Silvoni]

david.anastacio Thanks! i will have that in consideration from now on